<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
		<style type="text/css">
		 	#div1
			{
				width: 100px;
				height: 100px;
				background-color: blue;
			}
			.bigdiv
			{
				width: 200px;
				height: 200px;
				background-color: #000000;
			}
			.smalldiv
			{
				width: 100px;
				height: 100px;
				background-color: blue;
			}
		</style>
		<script src="../Js/jquery.js" type="text/javascript"></script>
		<script type="text/javascript">
			$(function(){
				$("#btn").click(function(){
					$("#div1").css.remove("smalldiv")
					$("#div1").css.addClass("bigdiv")
				})
			})
		</script>
		
	</head>
	<body>
		<input type="button" id="btn" value="按钮">
		<div id="div1" class="smalldiv"></div>
	</body>
	
</html>
